The present disclosure relates to an information input apparatus, information input method, and computer program for inputting a control command issued by a user to an apparatus to be controlled. In particular, the present disclosure relates to an information input apparatus, information input method, and computer program for inputting a control command issued by a user, such as a gesture of a hand.
In the environment where humans live, there are various types of products controlled by the user, such as home electrical appliances and information devices. There have been existing technologies configured to remotely control these types of apparatuses using a device, such as a laser pointer or remote control.
For example, there have been proposed remote control position notification systems that can notify the user of the position of a remote control (for example, see Japanese Unexamined Patent Application Publication No. 2008-224584), pointing systems that when the user waves, with a hand, a pointing device which is emitting a high-luminance diffusion light beam from its center, detect the position of the pointing device using multiple light receiving sensors, and display a pointer on the screen in accordance with motions of the hand while moving the pointer vertically or horizontally (for example, see Japanese Unexamined Patent Application Publication No. 2009-301564), and the like. However, in these related technologies, the user has to operate, with his or her fingers, a particular device for generating a signal for detecting the position or posture of the fingers, such as a remote control.
There have been also proposed remote controls configured to capture an image of an operator who is operating operation display means for displaying an operation button or menu and to detect an operation performed by the user on the basis of the shape and motion of a hand area detected from the captured image and the display on the operation display means (for example, see Japanese Unexamined Patent Application Publication No. 2010-79332). This related technology can recognize a gesture of the user using the outline of his or her fingers. However, since this technology uses only two-dimensional outline information, it is difficult to recognize a gesture stably unless the posture of the fingers is appropriate to the camera. For this reason, the user has to be conscious of the position of the camera. This imposes a large restriction on the posture of the user which is performing an operation. When the direction of observing the shape of the fingers, or the like, is changed, the outline of the fingers significantly changes. Accordingly, when a gesture is recognized in accordance with the outline, the recognition result becomes unstable, depending on the observation direction.
There have been also proposed image recognition apparatuses which three-dimensionally read a motion of the operator relative to a virtual operation surface, determine whether the motion is an operation, on the basis of the positional relationship between part of the operator and the virtual operation surface, and when the operator makes a motion in any of two or more virtual operation layers defined on the basis of this positional relationship, determine details of the operation on the basis of an operation type previously allocated to this virtual operation layer and the motion of the operator in this virtual operation layer (for example, see Japanese Unexamined Patent Application Publication No. 2010-15553). These image recognition apparatuses three-dimensionally track the fingers of the user using an image feature value. However, for example, when the lighting conditions are abruptly changed, it is difficult to stably match and track feature points among multiple frames in an image. Accordingly, the image recognition apparatuses seem to be low in recognition stability. Further, while these image recognition apparatuses can measure the three-dimensional positions of the feature points of the fingers, they do not detect the posture of the fingers themselves. Further, since these image recognition apparatuses recognize the user at a position relative to the camera, the user has to be conscious of the position of the camera. Further, to allow the user to perform an intuitive operation, the position of the camera has to be determined based on the relative positional relationship between the camera and the screen. Accordingly, the degree of freedom of choice is low.
There have been also proposed human motion determination apparatuses configured to use a captured image of a human which is making a predetermined motion and also use information on the depth of the captured image to determine the motion of the human, to extract feature points from the captured image to calculate a three-dimensional feature value, to track this three-dimensional feature value to calculate a four-dimensional trajectory feature value, and to use the four-dimensional trajectory feature value to determine the motion for each unit tracking time (for example, see Japanese Unexamined Patent Application Publication No. 2012-3364). However, to input an operation to these apparatuses, the user has to perform an operation on a virtual operation surface associated with a position indicated by a marker. Accordingly, a restriction is imposed on the position or posture of the user which is performing an operation.